1. Field of the Invention
The present invention relates to methods for the control of a gearbox arrangement by which torque generated by an engine is transmitted to a drive axle of a vehicle which includes a power shift transmission and a reverse module.
2. Description of the Related Art
During the shifting of the power shift gearbox, a jerk during shifting can be felt. This occurs because disk clutches shifting the various gear ratios of the power shift gearbox are engaged and disengaged hydraulically without modulation. This leads to torque variations in the drive-line of the vehicle, which are felt by the operator of the vehicle as jerk-like motion, thus resulting in reduced driving comfort. To avoid the jerking during shifting, U.S. Publication 2004/0237682 proposes that the drive clutch be brought purposefully into the slip region in a controlled sequence during the power shift process and subsequently be brought into engagement in a controlled and modulated manner.
The calibration of the control process to bring the drive clutch into the slip region is costly. It must be performed individually for each gearbox arrangement of a vehicle and, in certain circumstances, during the production and installation of the power shift gearbox and the drive clutch. This may be required and is costly, particularly if various vehicle components have different configurations of a power shift gearboxes and drive clutches.
Therefore, there is a need for a cost effective solution for placing the clutch in the slip region in a controlled sequence during the power shift process without the need for calibration of the control process for each gearbox arrangement.